Scavenger hunt's beginning with the old rejected article (5)
I believe the answer is:
hyena
'scavenger' is the definition.
(I've seen this before)
'hunt's beginning with the old rejected article' is the wordplay.
'beginning' suggests taking the first letters.
'with' says to put letters next to each other.
'the old' becomes 'ye'.
'rejected article' becomes 'na' (I can't justify this - if you can you should give a lot more credence to this answer).
The initial letter of 'hunts' is 'h'.
'h'+'ye'+'na'='HYENA'
Can you help me to learn more?
(Other definitions for hyena that I've seen before include "Carnivore with sloping body" , "one may be spotted" , "Carrion-eating, dog-like animal" , "African canine" , "one to laugh" .)